leak vs let cat out of the bag

leak

noun
  • A crack, crevice, fissure, or hole which admits water or other fluid, or lets it escape. 

  • The entrance or escape of a fluid through a crack, fissure, or other aperture. 

  • The gradual loss of a system resource caused by failure to deallocate previously reserved portions. 

  • A divulgation, or disclosure, of information previously held secret. 

  • The person through whom such divulgation, or disclosure, occurs. 

  • A loss of electricity through imperfect insulation, or the point where it occurs. 

  • An act of urination. 

verb
  • To allow fluid or gas to pass through an opening that should be sealed. 

  • To disclose secret information surreptitiously or anonymously. 

  • (of a fluid or gas) To pass through an opening that should be sealed. 

  • To pass through when it would normally or preferably be blocked. 

  • To urinate. 

  • To bleed. 

  • To allow anything through that would normally or preferably be blocked. 

let cat out of the bag

How often have the words leak and let cat out of the bag occurred in a corpus of books? (source: Google Ngram Viewer )